Recently applicable automotive paint finishing standards of increased severity as to protection of underlying metals from environmental attack and the ever increasing use of paints having limited contaminant dissolving capability are factors which have heightened automotive industry attention to improved filtration measures. Long recognized in the art is the propensity of auto finishes to exhibit voids or skips therein where oil, grease or chemically related matter is present in finish-detractive amount in paints applied to automobile bodies.
The automobile industry has heretofore looked to contaminant absorptive filters, disposed in on-line fluid flow communication with a pressurized coatings supply for on-line contaminant removal. Coatings application is typically performed by electrodeposition downstream of the filters. The filters are thus in-line with the electrodeposition equipment and have been constituted of a layer of one-hundred percent microfiber (very fine) polyolefin. This material, widely known for its high oil-absorptive properties, has had extensive past use in the static (non-flowing) pickup of oil from bodies of waters, e. g., as in the case of oil spills. Typically, a sheet of such material is cycled into oil-contaminated area at a rate commensurate with its oil-absorptive capacity, then into an oil scavenging or disposal station and then is disposed of or recycled into the contaminated area in refreshed absorptive character.
Application of this know oil absorptive material to commercially-required dynamic coatings flow in the automotive industry has occasioned severe flow rate reduction. The material is substantially interruptive of flow in short time periods, fiber plugs clogging very rapidly.